"I applaud Related Beal and Citgo for their willingness to come together in a collaborative way that will benefit the entire city," Walsh said in a statement. "The Citgo sign has become an important part of the community and I am delighted that both sides were able to agree on terms that will allow the sign to stay where it is."

Walsh said he met with both parties on Tuesday and offered space in City Hall as a neutral negotiation location. The agreement was reached on Wednesday afternoon.

"We are pleased to have reached a resolution where the sign will remain in place for decades to come and are grateful for the Mayor's leadership," said Kimberly Sherman Stamler, president of Related Beal. "We look forward to again collaborating with the City of Boston on plans for the redevelopment of Kenmore Square and to bringing increased economic activity, hundreds of jobs and a marquee office location to the area."

"We are proud that the Citgo sign has become a beacon in the Boston skyline and we are grateful to Mayor Walsh for his leadership in bringing the parties together," added Rick Esser, Citgo's vice president of supply and marketing. "This agreement ensures that the sign will continue to shine brightly for years to come. "

A Citgo sign has been part of Boston's skyline since 1940. The current sign atop 660 Beacon St. dates to 1965 and is visible over the famed left field wall at nearby Fenway Park.

Boston University agreed last summer to sell the building that houses the sign to Related Beal, a local development firm. Terms of that deal have not been disclosed.

Prior to the sale of the building, there had been concerns that new owners might decide to remove the sign.